Arms of larval seastars of Pisaster ochraceus provide versatility in muscular and ciliary swimming.

ABSTRACT: Larval swimming with cilia, unaided by muscles, is the presumed ancestral condition for echinoderms, but use of muscles in swimming has evolved several times. Ciliation and musculature of the arms of brachiolaria-stage larvae in the family Asteriidae provide unusual versatility in the use of muscles in swimming. The muscles affect swimming in two different ways. (1) Contraction of muscles moves the arms, propelling the larva. (2) Contraction of muscles changes orientation of the arms, thereby changing direction of ciliary currents and direction of swimming. New observations of the brachiolaria of the asteriid seastar Pisaster ochraceus demonstrate more versatility in both of these uses of muscles than had been previously described: the posterolateral arms stroke in more ways to propel the

SUBMITTER: George SB 

PROVIDER: S-EPMC6417731 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature